1. Field of the Invention
The present invention relates to a thrust plate assembly for a motor vehicle friction clutch with automatic wear compensation. The thrust plate assembly includes a housing connectable to a flywheel for common rotation about an axis of rotation, a pressure plate arranged substantially fixedly in terms of rotation in the housing and displaceable in the axial direction with respect thereto, a force accumulator supported between the housing and the pressure plate, a wear-adjustment device arranged in the support path of the force accumulator between the force accumulator and one component of the housing and the pressure plate having at least one adjustment element that is displaceable for wear compensation and is preloaded in a wear-adjustment direction, at least one play indicator arrangement including a blocking/detection element arranged on the one component and having a blocking section designed to act on the wear-adjustment device to prevent a movement of the at least one wear-adjustment element in the wear-adjustment direction, and a stop component which is in interaction or can be brought into interaction with a detection section of the blocking/detection element, the stop element being displacable with respect to the one component in the event of wear, the blocking/detection element being brought into a position for releasing the at least one adjustment element to move in the wear-adjustment direction by the interaction with the stop component.
2. Description of the Related Art
Thrust plate assemblies used in motor vehicle friction clutches with automatic wear compensation are known. These thrust plates include components which interact for wear compensation and/or also for wear detection for the new friction clutch which is to be assembled in such a manner with respect to one another that the friction clutch can have a clutch characteristic which remains constant throughout the entire operating life, without being significantly impaired by wear which occurs. During production and/or assembly of these known thrust plate assemblies, problems arise in arranging the components which interact for wear compensation and/or also for wear detection. In this context, it is particularly important for manufacturing reasons that the clutch disks or other components of a clutch of this type have certain manufacturing tolerances. However, the tolerances required for manufacturing reasons may result in a wear detection device or wear compensation device being unable to function correctly right from the start of the operating life.
The object of the present invention is to provide a thrust plate assembly and a method for setting a basic installation configuration of a thrust plate assembly for a clutch having wear compensation which can be used to ensure that the clutch provides an operating characteristic which remains substantially constant and is unaffected by wear throughout the entire operating life.
According to a first embodiment of the present invention, the object is met by a thrust plate assembly for a motor vehicle friction clutch with automatic wear compensation including a housing that is or can be fixed to a flywheel for common rotation about an axis of rotation, a pressure plate which is substantially fixed with respect to rotation in the housing and axially displaceable thereto, a force accumulator such as a diaphragm spring which is supported on the housing and on the pressure plate, and a wear-adjustment device arranged in the support path of the force accumulator between the force accumulator and one component out of the housing and the pressure plate. The wear-adjustment device has at least one adjustment element that is displaceable for wear compensation and is preloaded in a wear-adjustment direction. The thrust assembly also comprises at least one play indicator arrangement including a blocking/detection element arranged on the one component and designed with a blocking section to act on the wear-adjustment device to prevent a movement of the at least one wear-adjustment element in the wear-adjustment direction and a detection section which is in interaction or can be brought into interaction with a stop component which can be displaced with respect to the one component in the event of wear. The blocking/detection element is brought into a position for releasing the at least one adjustment element to move in the wear-adjustment direction in response to wear by interaction with the stop component which has a stop face region with which the detection section is or can be brought into interaction.
According to the present invention, the face sections of the stop face region may be arranged at different axial positions. To select the position of the face section which for interaction with the detection section, the positioning of the stop component can be adjusted with respect to another component bearing the stop component.
A thrust plate assembly of this type allows the interaction characteristic of the stop component with the detection section to be set by suitable selection of the positioning of the stop component. Suitable selection of the positioning of the stop component when the thrust plate assembly is new ensures that wear which occurs is compensated for and there is no need for a certain minimum wear to occur before the arrangement for wear compensation can become active in any respect right from the beginning of the operating life of a friction clutch which has a thrust plate assembly of this type.
By way of example, the thrust plate assembly according to the present invention may include a stop component arranged in a substantially fixed position in the axial direction on the other component while its stop face region is arranged so that it can move substantially transversely to the axis of rotation for selection of the position of the face section which is intended to interact with the detection section.
To hold the stop component in the desired way with respect to the other component, the other component may include a fixing element which is held in a rotationally fixed manner with respect thereto and pivotably bears the stop component. The required freedom of choice in setting the positioning of the stop component can be obtained by the fact that the stop component can be pivoted with respect to the fixing element by overcoming a frictionally locking connection which acts between the stop component and the fixing element. Furthermore, it is advantageous if the stop component can be fixed to the other component by the fixing element.
The configuration in which face sections may be positioned with different axial positions are to be provided for the desired setting option may be achieved when the stop face region of the stop component is designed with a surface region which is inclined with respect to a plane which is substantially orthogonal to the axis of rotation.
The thrust plate assembly of the present invention may also include a retaining element arranged for retaining the blocking/detection element and preventing movement of the blocking/detection element toward the wear-adjustment device when the blocking/detection element is moved into its position for releasing the at least one adjustment element.
The utilization of the available space is optimized if the one component comprises the pressure plate and if the other component comprises the housing.
According to a further embodiment of the present invention, the object is met by a thrust plate assembly for a motor vehicle friction clutch with automatic wear compensation, including a housing which is fixed or can be fixed to a flywheel for common rotation about an axis of rotation, a pressure plate which is arranged substantially fixedly in terms of rotation in the housing and can be displaced in the axial direction with respect thereto, a force accumulator such as a diaphragm spring supported on the housing and on the pressure plate, and a wear-adjustment device arranged in the support path of the force accumulator between the force accumulator and one component out of housing and pressure plate. The wear-adjustment device has at least one adjustment element which can be displaced for the purpose of wear compensation and is preloaded in a wear-adjustment direction. The thrust plate assembly further comprises at least one play indicator arrangement comprising a blocking/detection element which is arranged on the one component and is designed with a blocking section to act on the wear-adjustment device to prevent a movement of the at least one wear-adjustment element in the wear-adjustment direction. The blocking section is in interaction or can be brought into interaction with a detection section having a stop component which can be displaced with respect to the one component in the event of wear. In response to wear, the blocking/detection element may be brought, by means of the interaction with the stop component, into a position for releasing the at least one adjustment element to move in the wear-adjustment direction, the stop component having a stop face region with which the detection section is or can be brought into interaction.
The stop component is arranged on another component which can be displaced with respect to the one component out of the pressure plate and the housing in the event of wear. The stop component is arranged such that its axial positioning can be changed.
This embodiment of the present invention also utilizes the same basic effect, namely the possibility of being able to set the axial position of the stop face region, i.e. being able to set it axially in its region which interacts with the detection section.
In this embodiment, the stop component may be in threaded engagement with the other component and the axial positioning of the stop component with respect to the other component may be changed by rotation.
A thrust plate assembly constructed in this way may further include a fixing member via which the stop component can be fixed to the other component.
The axially adjustable positioning of the stop component with respect to the other component may be achieved by designing the stop component as a threaded bolt. The bolt together with at least one region of a bolt head forms the stop face region. In this case, the fixing member preferably comprises a lock nut screwed onto the stop component. In a thrust plate assembly according to this embodiment, a retaining element may be provided for retaining the blocking/detection element when the blocking/detection element is moved into its position for releasing the at least one adjustment element, such that the blocking/detection element is prevented from moving toward the wear-adjustment device. Furthermore, in this embodiment, the one component comprises the pressure plate and the other component comprises the housing.
According to a further aspect of the present invention, the object is met by a method for adjusting a basic installation configuration of a thrust plate assembly according to the present invention, the method including the following steps:
(a) displacing the pressure plate with respect to the housing in the axial direction, counter to the preloading force of the force accumulator, beyond a basic installation position of the pressure plate, which basic installation position the pressure plate adopts, after assembly of the thrust plate assembly together with at least one clutch disk and a flywheel, with a substantially unworn clutch disk, in the engaged state when bearing on the clutch disk, into an installation preparation position, and
(b) setting an interaction positioning of the stop component with respect to the other component in such a manner that the stop face region of the stop component is in contact, by means of one of its face sections, with the detection section after the installation preparation position has been reached.
The significant aspect of this procedure according to the invention is that the pressure plate and therefore also the force accumulator and/or the detection section are first moved into a position which they will not adopt during actual operation. The interaction positioning of the stop component is then performed while the pressure plate is in the installation preparation position. This ensures that when the pressure plate moves out of this installation preparation position, the detection section starts to interact with the stop component and allows for wear compensation.
Furthermore, step (b) may include pivoting the stop element counter to a frictional connection between the stop element and a fixing element which bears the stop element on the other component. The fixing element is preferably being held in a rotationally fixed manner on the other component.
To prevent undesirable wear compensation from occurring before assembly of the thrust plate assembly with a flywheel, i.e. before a friction clutch is completed, the stop component is provided with an axial movement play with respect to the other component after the interaction positioning of the stop component with respect to the other component has been set. The extent of the axial movement play at least corresponds to the movement travel of the detection section which occurs under maximum relaxation of the force accumulator. The stop component may be fixed to obtain the interaction positioning set in step (b) after the thrust plate assembly has been assembled with the at least one clutch disk and the flywheel, thereby eliminating the axial movement play with respect to the other component. According to an alternative embodiment, the occurrence of undesirable wear compensation of this nature prior to assembly with a flywheel may be prevented by holding the pressure plate in or close to the installation preparation position until after the assembly of the thrust plate assembly with the at least one clutch disk and flywheel after the interaction positioning of the stop component with respect to the other component has been set.
According to a further embodiment of the present invention, the object is met by a method for adjusting a basic installation configuration of a thrust plate assembly according to the present invention, the method comprising the following steps:
(a) displacing the pressure plate with respect to the housing in the axial direction, counter to the preloading force of the force accumulator, beyond a basic installation position of the pressure plate, which basic installation position the pressure plate adopts, after assembly of the thrust plate assembly together with at least one clutch disk and a flywheel, with a substantially unworn clutch disk, in the engaged state when bearing on the clutch disk, into an installation preparation position, and
(b) setting the axial positioning of the stop component with respect to the other component in such a manner that the detection section is in contact with the stop face region after the installation preparation position has been reached.
In this embodiment, suitable setting of the axial position of that surface region of the stop component which interacts with the detection element ensures that wear compensation is possible right from the beginning of operation of a friction clutch containing the thrust plate assembly.
The stop component may be fixed with respect to the other component after the axial positioning of the stop component has been set. Furthermore, the pressure plate is preferably held in or close to the installation preparation position until after assembly with the at least one clutch disk and the flywheel after the axial positioning of the stop component has been set.
To simplify the entire operation of constructing a friction clutch having a thrust plate assembly according to the present invention, the installation preparation position of the pressure plate is a position in which the force accumulator acting on the pressure plate is deformed into a predetermined positioning, preferably a positioning which the force accumulator adopts in the engaged state of the clutch when the friction clutch has been assembled. Furthermore, the installation preparation position of the pressure plate may comprise a position in which the force accumulator acting on the pressure plate produces a predetermined reaction force, preferably a reaction force which the force accumulator generates in the engaged state as a pressure-exerting force when the friction clutch has been assembled.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.